As is known, plant safety is an important factor in any given manufacturing operation. In this connection, and more particularly, importance lies in the knowledge that certain equipment remains in optimal operative condition, irrespective of whether or not certain components are in a repair stage and/or are contemplated for repair. The government, through OSHA, i.e. Occupational Safety & Health Administration, is placing an increasing number of restrictions, throughout industry, to achieve maximum safety for the workman.
One particular ground of concern is in connection with heavy machinery, where knowledge of other personnel involved in a repair/maintenance operation, or at least their presence, is known to fellow workers, i.e. where, for example, provision is made for absolute shut-off of particular equipment.